Mega Code Archive
GenerateSignature
<![CDATA[
package com.ack.security;
import java.io.FileInputStream;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import com.ack.security.ByteUtils;
/* Generate a DSA signature */
class GenerateSignature {
public static void main( String[] args ) throws Exception {
// get hold of a DSA key generator implemented by SUN
System.out.println( "get key pair generator..." );
java.security.KeyPairGenerator keyGen = java.security.KeyPairGenerator.getInstance( "DSA", "SUN" );
// randomize based upon SHA for SUN
java.security.SecureRandom random = java.security.SecureRandom.getInstance( "SHA1PRNG", "SUN" );
keyGen.initialize( 1024, random );
// create a key pair
java.security.KeyPair pair = keyGen.generateKeyPair();
java.security.PrivateKey priv = pair.getPrivate();
java.security.PublicKey pub = pair.getPublic();
System.out.println( "## generated key pair..." );
// create a signature based upon SHA with DSA implemented by SUN
java.io.FileInputStream fis = new java.io.FileInputStream( "hello.txt" );
byte[] realSig = SignatureUtil.signData( fis, priv );
System.out.println( "## signed information..." );
// output the signed file
com.ack.security.ByteUtils.saveBytesToFile( "hello.sig", realSig );
System.out.println( "## save signed file to hello.sig ..." );
// save the public key to file as well
com.ack.security.ByteUtils.saveBytesToFile( "hello.pubkey", pub.getEncoded() );
System.out.println( "## save public key to hello.pubkey" );
System.out.println( "done!" );
}
}
]]>